The present disclosure relates to the field of wind driven turbines, i.e., wind engines. Conventionally, a wind engine is classified as a horizontal axis wind engine or a vertical axis wind engine based on the orientation of rotating axes of its vanes. For vanes of the vertical axis wind engine they are pivotally mounted in a frame. The frame is fixedly coupled to a vertical axis. Its transmission is provided near the ground. To the contrary, in the horizontal axis wind engine each vane has its horizontal axis provided above the ground by a relatively long distance Moreover, each of a plurality of vanes of a vertical axis wind engine can adapt itself to wind by providing a wide contour in a windward condition for fully taking advantage of the force of wind and thus for generating larger torque. To the contrary, each vane can adapt itself to wind by providing a narrow contour in a leeward condition for decreasing wind friction. As an end, wind's rotation on the vanes can be maximized for rotating the wind engine. As such, many power companies have spent much time and cost in research and development of commercial wind engines which almost all are vertical axis type wind engines due to the above reasons. The vertical axis wind engine comprises a plurality of vanes of flat surface each pivotally mounted near a free end of one of a plurality of arms of a star configuration. The arms are adapted to rotate in response to wind blowing over surfaces of the vanes. Also, the vanes orbit a central, vertical axis. Each vane can adapt itself to wind by providing a wide contour in a windward condition for fully taking advantage of the force of wind. To the contrary, each vane can adapt itself to wind by providing a narrow contour in a leeward condition for decreasing wind friction. In prior art wind turbines, an abrupt operation often occurs when the wind engine rotates. That is, its operation is not smooth. Further, the vanes tend to cause the wind engine to rotate intermittently due to centrifugal force. As such, the rotating speed of the wind engine may decrease greatly. And in turn, both the arms and the vertical axis rotate in a speed less than wind speed. The presently described wind turbine avoids this problem by providing very low mass vanes.
Like reference symbols in the various drawings indicate like elements.